This invention relates generally to a threaded fastener assembly and, more particularly, to a fastener assembly of the type in which a sleeve is adapted to be preassembled with and captivated axially on the shank of a threaded fastener. Even more specifically, the invention relates to a special-use fastener assembly of the type in which the sleeve must be capable of moving axially along the shank through a limited range.
A fastener assembly of this general type is disclosed in my aforementioned copending application. In that assembly, the shank of the fastener is formed with a lower threaded section and an unthreaded upper section, there being an axially facing shoulder defined at the junction between the two sections. A resiliently yieldable retainer grips the unthreaded section of the shank and engages the shoulder. The interior of the sleeve is shaped and dimensioned to permit the sleeve to be slipped onto the shank and, after the retainer has been installed, to enable the sleeve to slide axially through a limited range on the shank while being captivated thereon by the coaction of the retainer and the shoulder.
In certain applications of the fastener assembly, it is a requirement that fully formed threads on the fastener at least reach the bottom of the sleeve and preferably extend up into the sleeve when the fastener assembly is in its fully installed position. It also is a requirement that the fastener be capable of sliding upwardly relative to the sleeve to a point where all of the threads are located inside of the sleeve. The fastener assembly disclosed in my aforementioned application can meet these requirements as long as the length of the sleeve is greater than one-half the length of the fastener shank but cannot satisfy these criteria if the length of the sleeve is less than one-half the length of the shank.